This invention relates to a detachable drain system for the multiple fuel segments which provide fuel to fuel nozzles projecting into an aircraft gas turbine combustion chamber.
Unburnt fuel drainage is of vital importance when aircraft gas turbines are shut down, either after a period of operation or where the starting cycle is not completed because combustion did not begin. Combustion chamber drain arrangements are shown, for example, in U.S. Pat. No. 2,846,845, issued Aug. 12, 1958 and assigned to the same assignee as the present invention. A typical fuel drain manifold system may include multiple connectors which employ nuts with lockwires, requiring special tools to install and remove with such operations being relatively difficult and time consuming. It is important to prevent fuel in the fuel supply lines from leaking through the nozzles into the combustion chamber when the gas turbine is shut down because of the tendency for the fuel inlets to clog due to the carbonization of the fuel as it issues slowly from the heated nozzles. Furthermore, fuel drainage prior to the combustion chambers reduces the danger of flaming which exists when unburned fuel is present in quantity in the combustion chamber. Accordingly, the leakage of fuel either from unburnt fuel or from a leak at a joint in the fuel system in the "hot section" or fire zone of the engine should be prevented or contained.
However, there may be thirty or more fuel nozzles supplied from a typical fuel manifold such that the proper installation and detachment of the fuel drain lines to the drain manifold typically requires special tooling, considerable time., and skill. Moreover, the multiple spaced nozzles and fuel segment lines increase the difficulty in properly positioning and connecting, or disconnecting, the system.